Telegraphy



T. 3,0021% TELEGRAPHY.

APPLICATION FILED DEC-5, 1913.

Patented May 11, 1920.

5 SHEET5SHEET B- DIXON. TELEGRAPHY.

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Patented May 11, 1920.

' 5 SHEETS-SHEET 2.

T. B. DIXON.

TELEGRAPHY.

APPLICATION mu) nsc.5, 191s.

Patented May 11, 1920.

A 5 SHEETSSHEET 4- T. B. DIXON.

TELEGRAPHY.

APPLICATION FILED 050.5. 1913.

1,339,549. atented May 11, 1920.

5 SHEETSSHEET 5.

THOMAS IB. DIXON, or NEW YORK, N. Y.

TELEGRAPH-Y.

Specification of Letters Patent.

Patented May 11, 1920.

Application flied December 5, 1913. Serial. No. 804,873.

To all whom it may concern:

Be it known that I THOMAS B. DIXON, a citizen of the United states of America, and

'a resident of New York, in the county of nection with lines of very great retardation, A such as submarine cables.

In the method of transmitting and receiving telegraphic signals, most commonly used on long submarine cable lines, dots and dashes of the telegraphic code are represented by current pulses of different directions, but of approximately the same duration, a positive pulse for example, indicating a dot, and a negative pulse, a dash. The signals are received by an instrument, termed a siphon recorder which is in its nature a very sensitive galvanometer the moving member of which is provided with a pen (this pen being, in practice, a siphon tube) which traces a wavy line on a moving record strip, waves to one side of an imaginary center on such strip designating dots and waves to the other side of such imaginary center (lesignating dashes. At low speed, the signals thus transmitted and received come outclearly; but as the speed of transmission rises, the signals become indistinct, until, at what would be a very moderate speed for transmission over a land line, the si nals become so indistinct as to be unintelligible.

My present invention comprises means for amplifying telegraphic signals, particularly signals transmitted as described through circuits of very great retardation, whereby distinct signals are produced at speeds of transmission at which signals, if received in the ordinary way, would be unintelligible; and by the means for amplifying signals, herein described, I have been able to reach a speed of transmission very much greater than any practicable speed of transmission heretofore possible over the same or corresponding lines.

As above stated, the receiving instrument commonly used is in its nature a galvanometer. The currents which operate this galvanometer are so exceedingly feeble that I have not found it practicable, in practice, to amplify such signals materially. by mechanical means; for mechanical means for amplification of signals necessarily involves moving parts which have inertia, the effect sired lenggh, but which is entirely without inertia. herefore the length of the light beam may be varied as desired or required, thereby efi'ecting movement of the pointer through any desired range, without increasing the inertia of the movable galvanometer member.

As is well known, selenium is a substance the electrical resistance of which varies greatly according as it be in light or in darkness. In darkness selenium has very high electric resistance, but when brightly illuminated the resistance of the selenium falls very greatly. Other substances have similar properties. Actinium for example has a relatively low resistance in darkness and a relatively hi h j resistance when brightly illuminated. nd my radio-electrosensitive element is not necessarily either a selenium cell or an actinium cell; for a thermal couple such as is commonly con-v tained in a thermopile will generate current variably if acted upon variably by heat rays. prefer, however, to use selenium cells as the radio-electro-sensitive elements employed according to my invention, as in practice I have found them very reliable, and I so locate one or more of these cells that the beam of light, variably deflected by the galvanometer reflector, as previously described, will move across the face or faces of such cell or cells. I connect such cell or cells to an electric circuit or circuits containing a source or sources of electric energy, for example, a primary battery, and the variation of resistance of the selenium cell or cells, due to the variable illumination of such cell or cells, causes variation in current flow through such circuit or circuits capable of actuating the moving element of a galvanometer or like instrument. The receiving instrument employed by me in the circuit of such selenium cell or cells is commonly an ordinary siphon recorder; the amplification of the signals of the cable circuit, due to the variable deflection of a beam of light by a reflector, actuated by such si als, over the surface or surfaces of a se enium cell or. cells themselves in the circuit of the si hon recorder, being so great that intelligible and very clear signals are produced at speeds far above the s eeds at which intelligible signals would bo produced if the siphon recorder were in the cable circuit itself, according to former practice. I have not found that, by so amplifying. the signals of the cable, objectionable peculiarities are impressed upon such signals by the amplifying apparatus. To the contrary, the signals remaln of the same character as before, except that their quality is improved, but the deflections of the movable member of the siphon recorder are so very much greater than they would be if that siphon recorder were directly in the cable circuit, that intelligible and very clear signals are produced at s eeds of transmission far above what has een practicable heretofore on similar circuits.

My invention comprises a pair of selenium cells or other radio-'electro-sensitive devices, or a plurality of, pairs of cells or devices, together with means for varying the action of radiant energy in opposite senses simultaneously upon the two cells of such pair or of each such pair, together with signal receiving means, and circuit means as hereinafter described, whereby as the action of radiant energy is decreased upon one cell of such a pair and is correspondingly increased upon the other cell of such pair, the two cells co- 0 erate to produce cumulative or additive e ect on such signal receiving device.

The object of my invention is to increase the speed and certainty of transmission of signals through electric circuits, particularl circuits of high retardation.

he accompanylng drawings illustrate diagrammaticall the means for amplification of telegrapi signals, herein described. In said drawings:

Figure 1 shows diagrammatically an arrangement of transmitting, signal-amplifying, signal-receiving and signal-repeating means embodying m invention.

Fig. 1 is a detai diagram showing the transmittirig circuits of repeating relays 27 and 28 of ig. 1.

Fig. 2 is a diagram illustrating the use of one radio-electro-sensitive element in lieu of the two radio-electro sensitive elements employed in Fig. 1 and further illustrates the fact that in the arrangement shown in Fig. 1 each radio-electro sensitive element 14 acts, in a measure, independent of the other.

Fig. 3 shows an alternative arran ement of circuits for use when a pluralit 0 radioelectro-sensitive elements are em 0 ed, such elements being located in a RV eatstone bridge. 7

Fig. 4 is a diagram somewhat similar to Fig. 3, but indicating connections which may be employed when four radio-electrosensitive elements are employed in a Wheatstone bridge circuit; Fig. 4 also illustrating the light beam and means for producing it, the line alvanometer and the coil and magnets of t e receiving siphon recorder.

Fig. 5 is a diagram illustrating, in conventional VVheatstone bridge arrangement, the location of the several radio-electrosensitive elements in the arms of the Wheatstone bridge of Fig. 4.

Fig. 6 is a diagram illustrating means for repeating the amplified signals into another circuit.

Fig. 7 is a similar diagram illustrating an alternative repeating arrangement, and illustrating the use of a curbing circuit and curbing windings on the coil of the line galvanometer.

Fig. 8 is a diagram, similar to Fig. 4, illustrat' g another arrangement whereby four radio-electro sensitive elements may be emplrgyed in cooperative relation.

ig. 9 is a fragmentary perspective elevation of the repeating relay illustrated in Fig. 6, and Fig. 10 shows a detail front elevation and partial section of the principal portions of the said receiving relay.

Fig. 11 is a diagram illustrating a further alternative repeating arrangement.

Fig. 12 shows, more or less diagrammatically, an alternative arrangement of contacts which may be employed, and is particularly adapted for use in a re eating instrument such as illustrated in igs. 9 and 10, and illustrated'diagrammatically in Figs. 6, 7 and 11.

Referring first to Fig. 1 numerals 1 and 1 designate two telegraphic keys (shown in this case, as keys designed to be operated by hand) which operate corresponding trans mitting relays 2, 2" by closing and breaking branch circuits of battery 3. The key 1, when depressed, will close circuit from this battery to the relay 2, and the key 1, when depressed, will close circuit to the relay 2. The operation of either of these relays places a transmitting battery 4 in circuit to send current into the cable 5, which cable, as shown, connected for working in one direction, is provided with the usual block condensers 5 at its two ends. The currents sent into the cable will have a polarity of positive to line and negative to earth when the relay 2* is operated, and a polarity of positive to earth and negative to line when the left hand relay 2 is operated. At the receiving end of the cable there is a galvanometer comprising a suspended coil 6, located in a magnetic field, and in a circuit extending from the cable, through the corresponding condenser 5,'to ground. The receiving galvanometer further comprises a mirror 7 suspended by suspension fibers ,9 to swing freely, and provided at its lower end with a T-shaped piece 8 connected to coil 6 by two delicate fibers 10; the points of connection of these fibers 10 to the piece 8 being, preferably, closer together than the points of connection of said fibers to the coil 6, so that for any given angular movement of the coil 6, the an lar movement of the mirror 7 is greater. suitable source of light, 11, is provided (the particular source diagrammatically indicated being the carbons of an electric arc lamp) and the light beam from such source passes through suitable lenses 12 and a screen 13 to the reflec tor 7, and thence is reflected variably to selenium cells hereinafter mentioned. The beam of light from the source 11 is shaped by con'densing lenses 12 and the screen 13 so that its cross section, at the point where it strikes the selenium cells 14, would be approximately square but for the fact that it passes through a lano-cylindrical lens 15 which condenses it in one direction a, condenses it vertically with the lens 15 positioned as shown in the drawing). The beam of light is therefore approximately rectangular where it strikes upon the selenium cells. The selenium cells 14 have their terminals connected with batteries 16 and 17 in circuit branches 18 of a circuit 19 connected to the coil 20 of a siphon recorder 20; which recorder is itself a specific form of galvanometer. When the light beam is in central position with respect to the two selenium cells, as indicated in the drawing, then, assuming the batteries 16 and 17 to be equal, and the resistances in the circuit branches 18 (such resistances includin the resistances of the selenium cells themse ves) to be equal when the two cells 14 are equally illuminated, the two batteries 16 and 17 oppose each other in the circuit 19 and no current will flow through the coil 20 of the siphon recorder. When, however, the light beam is deflected from its central or zero position, indicated, to one side or the other (for example, when the light beam is deflected from left to right, such deflection corresponding it may be assumed, to a dot signal transmitted through the cable 5) current from battery 17 will predominate and flow through circuit 19 and coil 20 of the siphon recorder, thus causing movement of the siphon tube or pen 21. If the deflection of the light beam is from right to left (such deflection corresponding to a dash signal) My signal amplifying device may also be i used as a repeater; to this end the coil 20 may operate a contact point 24 (shown in the drawing as mounted on the siphon tube 21 itself) which contact point 24 plays between contact stops 25 and 26 in circuit, respectively, with repeating relays 27 and 28 in circuit with a battery 29, one side of this battery being connected by a conductor 30 to contact point 24, and the other side of this battery being connected,by conductor 31, and through repeating relay 27, to contact stop 25, and being also connected by a conductor 32, through repeating relay 28, to contact stop 26.

Vhen the coil 6 of the receiving galvanometer is in central position, and, therefore, when the light beam playing upon the selenium cells is in zero position, one half of each of the selenium cells 14 is illuminated, the other half of each such cell being unilluminated. The resistances of the two selenium cells should then be equal; but since it is difficult to obtain two selenium cells of exactly the same resistance, I have indicated in the drawing adjusting variable resistances 33 and 34, whereby the resistance of the two circuit branches 18 may be made equal.

The operation of the system is as follows:

Supposing the transmitting key 1 to be depressed, then the negative pole of battery 4 is connected to the cable through the contacts of the relay 2*, and the positive pole of battery 4 is connected to ground through the contacts of the relay 2; and a current wave is transmitted through the cable 5, causing deflection of coil 6 of the receiving galvanometer (and it may be assumed that such deflection is to the right), which in turn causes the beam of light playing on the selenium cells 14 to move to the right, decreasing the illumination of the left hand cell 14 and increasing the illumination of the right hand cell 14, and so increasing the resistance in the circuit branch 18 containing battery 16, and decreasing the resistance in the circuit branch 18 containing battery 17, thereby disturbing the balance theretofore existing between these two branch circuits and causing flow of current-through circuit 19 which, in turn, causes deflection of coil 20, moving the tracing end of siphon tube 21 (and it may be assumed that Such motion is to the right). Similarly, de-

cell 14 being replaced by a balancing resistance 14 circuit arrangements being otherwise similar, the beam of light being indicated by a dotted rectangle 11. It will be seen that while, with the beam of light in the position shown, and the resistance 14 adjusted to exactly balance the resistance of the selenium 14 so illuminated, the batteries 16 and 17 neutralize each other respectively in the circuit 18, yet if that beam of light be moved, the consequently varied resistance of cell 14 will cause a current from the one battery or the other to pass through circuit 18 and deflect the coil 20.

Various arrangements of circuits including the selenium cells and the coil 20 may be used. In Fig. 3, I indicate a Wheatstone bridge arrangement wherein the two selenium cells 14 are each in one arm of the bridge, the coil 20 being in the cross wire 35 of the bridge, the latter being designated generally by the number 36.

Instead of employing one cell only, or two cells only, a larger number of selenium cells may be employed. In Fig. 4 I 'show one means for employing four selenium cells designated respectively by reference characters 14*, 14 14 and 14 The circuits are those of a W'heatstone bridge 36, as will be more apparent from Fig. 5, wherein thecircuits are shown in conventional Wheatstone bridge arrangement, without regard to the relative physical positions of the various selenium cells; the coil 2O bein in the cross wire 35 of the bridge. The principle of the \Vheatstone bridge being well known, it will be apparent that if movement of the beam of light 11 increases the illumination of "elenium cells 14 and 14 and decreases the illumination of cells 14 and 14, there will be a flow of current in one direction through the cross wire 35 of the bridge, producing a deflection of coil 20; while if the change in illumination of the selenium cells be in the opposite sense, there will be a flow of current through the cross wire 35 in the opposite direction.

In the alternative arrangement shown in Fig. 8, the screen which shapes the light beam, which screen is in this figure designated by numeral 13*, is provided with two apertures, dividing the light beam into two separate beams both of which are directed upon and are reflected by the same mirror 7, and, passing through the plano-cylindrical lens 15 impinge, one u )on radio-electro sensitive elements 14 an 14", the other upon radio-electro-sensitive elements 14 and 14. The two beams move together and as the illumination of elements 14 and 14 is increased, the illumination of elements 14 and 14 is increased; and vice versa. These cells are preferably employed in a Wheatstone bridge, as illustrated in Fig. 5. The arrangement shown in Fig. 8 is desirable when, as result of adjustment for high speed operation, the coil 6 of line galvanometer has a relatively small amplit'ide of movement.

I have found that the sharpness of difinition of the signals, and the permissible speed of transmission, are greatly increased by the provision, in connection with the coil 6 of the receiving galvanometer, and also in connection with the coil 20" of the siphon recorder, of a magnetic shunt 37, (see Fig. 1) i. e., a resistance of hi h inductive value such as is commonly used in connection with siphon recorders in cable systems; such shunted inductive resistances having, as is well known, the effect of s uarin the signals.- And sometimes, as idilicated particularly in Fig. 11, I employ, in connectlon with one or another of these magnetic shunts, a shunted condenser 38. By proper adjustment of resistance and inductance of the magnetic shunt or shunts 37, and by proper adjustment of the reactance of the shunted condenser 38, I can so time or tune the circuits as to produce conditions most desirlable for the reception of telegraphic signa s.

In Fig. 6 I illustrate a repeating arrangement which is preferable to that indicated in Fig. 1, and in Figs. 9 and 10 I illustrate the mechanical construction of the repeating instrument indicated diagrammatically in Fig. 6. In Fig. 6, as before, numeral 7 designates the reflector operated by coil 6 (I do not show in Fig. 6, the source of the light beam reflected by this reflector 7) and numerals 14 indicate the selenium cells and numeral 20 desi ates the coil of the galvanometer contro led by the selenium cells. This coil, which is mounted to swing freely, carries an arm 40 rovided with insulation pieces 41 and 41* a apted to engage and actuate mechanically, contact pieces 42 and 42 carried by freely swinging contact arms 43 and 43; and beneath these arms 43 and 43 are other contact arms 44 and 44, also mounted to swing freely, and each provided with a contact screw 45 or 45 and with an insulation stop 46 or 46. As shown particularly in Figs. 9 and 10, the contact arms 43 and 43 are carried by delicately mounted shafts 47 having jewel bearings 48 which jewel bearings serve to insulate the contact arms 43 and 43 from the supports of such bearings; the weight of such shafts 47 and the arms 43 carried thereby, being carried by jewel step bearings 49. The contact arms 44 cuit 5 to deflect the coil 6 to one and 44 are carried by similar shafts 47 for which shafts 47 however, jewel bearings are not provided, customarily, as insulation of these arms 44 and 44 from their supports is i not required, and some slight frictional retardation to motion of these arms 44 and 44 is desired, such retardation bein supplied, not only by the slight friction 0 shafts 47 in their bearings, but also by friction springs 50. A support 51 is provided with insulation stops 52, which serve to limit the motion' of contact arms 44 and 44 toward the center. Current is supplied to contact arms 43 and 43 through very flexible conductors 53, and current is similarly supplied to contact arms 44 and 44 by very flexible conductors 54.

Contact arms 43 and 43 are provided with light tension springs 55 and 55 respectively, tending to hold the contact piece, 42 or 42, of that arm, 43 or 43. against the insulation piece 41 or 41 of the arm 40.

For each of the contact mechanisms 43- 44 etc., and 43 -44, a separate battery, 56 or 56, is provided, current passing from this battery through conductor 57 or 57 to arm 43 or 43 and current passing from the other side of the said battery through the magnet of a transmitting relay 58 or 58 and thence through a conductor 59 to contact arm 44 or 44. To reduce sparking at the contact points of contact mechanisms 43--44 and 43 -4 4", I provide shunted condensers 60 and 60. a

The operation of this instrument lows:

Supposing a current pulse in the cable cirside or the other, so changing the illumination of the selenium cells 14, the coil 20 will be de flected to one side or the other, according to the direction of such current pulse in cable circuit 5. We will assume that the coil 20 is moved to the left in Fi 6. Such movement causes the arm 40 o coil 20 to move is as folthe contact arm 43 to the left, the contact piece 42 of the arm 43 immediatel making contact with contact piece 45 o arm 44, and so closing circuit through the magnet of repeating relay 58. The contact arm 44,

being mounted to move quite freely,' moves with contact arm 43 as soon as contact pieces 42 and 45 have made contact, so that the making of such contactdoes not limit appreciably the movement of the c011 20; but as soon as coil 20 starts to move back, the spring 55 draws contact arm 43 away from contact piece 45, so breaking the circuit of repeating relay 58; and spring 55 then restores contact arms43 and 44to normal position as rapidl as the movement of coil 20 will permit. elays 58 and 58 operate, as shown, repeating contacts, whereb the signals in cable circuit 5 are repeater into another circuit 5".

Similarly, movement of the arm 40 to the right of Fig. 6 will cause the operation of the contact mechanism 43-44 in the same manner, and the operation of transmitting relay 58 in the same manner.

It is convenient to provide the coil 20 with a siphon tube 21 adapted to write upon a moving tape 22, in order that the signals received may be recorded and that there may be a check upon the signals transmitted by relays 58 and 58*. And for a further check upon the signals transmitted by relays 58 and 58* a further recorder 61 of suitable type may be provided.

In Fig. 7 I show an arrangement of circuits and instruments similar to that of Fi 6, except that one batter 62, is provi ed for the two contact mec anisms 43- 44 and 4344, instead of a separate battery for each such contact mechanism, and except that circuits are provided whereby the change of illumination of selenium cells 14 due to a deflection of mirror 7, acts upon coli 6, first to assist the movement of such coil and render it more prompt in its movement and then to curb the movement of such coil. To this end, the coil'6 is provided with a supplemental winding 63 in a circuit 64 arranged to be reversed by pole changing contact mechanism 65 and 65 with which relays 58 and 58 are provided. Supposing coil 6 to be deflected and to vary the illumination of selenium cells 14, and thereby to; cause deflection of coil 20*, current passes through circuit. 64 (connected in parallel, as shown, to the circuit which operates coil 20) through the supplemental winding 63 of coil 6, in a direction to enhance the motion of such coil 6, thereby, making the motion of coil 6 more prompt and rapid; but as soon as one of the rela s 58 or 58 has been operated, through t e operation of coil 20", the current through such supplemental winding 63 is reversed, whereby-the deflection of coil 6 is checked; such current through 63 being insufficient, however, to cause return movement of coil 6 during the period of a normal signal.

In Fig. 11 I illustrate a further and preferred repeating arrangement, very similar to that shown in Fig. 7 except that the two repeating relays", here designated by numorals 58 and 58 are provided each with two separate magnets 58* and 58' for relay 58 and 58 and 58 for relay 58; and except that the armatures of relays 58 and 58 are provided with adjustable weights 66 whereby the normal rate of movement of said armatures maybe varied; and except that a spring actuated jockey 67 is provided for each relay, such jockey bearing against the V-shaped end of the armature of the relay. The contact points'45 and 46 and 45 and 46. of the repeater are, furthermore, insulated from each other and are in separate magnet 58 will be energized and will position to which it has been circuits, contacts 45 and 45 controlling magnets 58 and 58 respectively, and contacts 46 and 46 controlling respectively, magnets 58 and 58 It will be apparent that when contact arm 40 is deflected toward the left,

actuate the armature of relay 58", such armature, when so actuated being held in the moved, by the jockey 67, until magnet 58 is energized, and positively moves such armature back against the resistance offered by jockey 67; and energization of magnet 58 will occur only when the coil 20 is well back on its return swing toward the central position.

Similarly, if coil 20 be deflected toward the right, magnet 58 will be energized and will operate the armature of relay 58, which armature will be held in its resulting position, by the jockey 67, until well after the return swing of the coil 20 toward its central position, during which return swing magnet 58 will be energized and will restore the armature of relay 58 to normal position. The use of separate magnets for moving the armatures in these relays 58 and 58 from and toward normal positions with separate contacts operated by arm 40 of coil 20 for actuating the magnet and the adjustable weights 66 on the armatures of the relays and jockeys 67 acting against said armature, provide a very wide range of adjustment of the extent of return swing of the coil 20 which may occur before the repeating relay, 58 or 58 is actuated as a result of such return swing. In Fig. 11 I also illustrate, in the curbing circuit 64 of coil 6, inductive resistance 68 and a shunted condenser 69 whereby such curbing circuit may be tuned or timed as to its curbing action upon coil 6.

In Fig. 12 I illustrate diagrammatically alternative contact mechanism which may be substituted for the mechanism 40 to 46 and 40 to 46 illustrated in Figs. 9 and 10 and illustrated diagrammatically in Figs. 6, 7 and 11. In this alternative arrangement, the arms 43 and 43 are provided with contact segments 70 and 70 respectively, coacting with other contact segments 71 and 71 of delicately pivoted levers 72 and 72 which levers are connected by fibers 73 and 73 to the arm 40 of coil 20 and are provided with retractile springs 74 and 74 and with suitable stop fibers 75 and 75 and these levers 72 and 72 are further connected by fibers 76, 77, 76 and 77, to the arms 44 and 44; there being slight slack in the fibers 76, 77 and 76 and 7 7, when the levers 73 and 73 are in middle position with reference to arms 44 and 44. Each contact segment 71 and 71 is provided over a portion of its face with insulation 78 and 78' respectively. It will be apparent that circuit will be completed when, by the motion of arm 40 the conducting portion of one of the segments 71 or 71* is brought into contact with the segment 70 or 70.

Contact points, such as 42, 45, 46, 42*, 45 and 46*, illustrated in Fi s. 6, 7 9 and 10, are likely to stick very slightly, when they should break circuit promptly; such sticking being due to adhesion, and other reasons. Similar sticking does not occur, at least to the same extent, between contact segments, such as 70 and 71, which roll upon one another; for which reason an instrument provided with contacts such as illustrated in Fig. 12 will be more sensitive, other things being equal, than an instrument provided with contact points such as shown in Figs. 9 and 10.

I use the term signal-translating means in certain of the following claims, to include any means for reproducing si nals, either visually (as by marking the signals on a tape or other record sheet) or by movements of a beam of light, or audibly (as by operating a suitable sounder) or by repeating the signals into another circuit.

I use the term illumine and like terms, with reference to the action of radiant energy (a light beam, for example) on radioelectro sensitive means (selenium cells, for example) as inclusive of action of radiant energy of all classes on radio-electro-sensitive means of all types.

By the method of and means for amplifying cablesignals herein illustrated and described, I have been able to attain a speed of transmission of three hundred and seventy letters per minute over a cable about eight hundred miles in length and having an ohmic resistance of eight thousand ohms and a static capacity of two hundred and sixty micro-farads, z. e., a K R factor of 2,080,000, the signals, as recorded on the tape of a siphon recorder being substantially perfect in form and entirely readable. Still hi her speed of transmission has been obtained by me over this cable when, owing to temporary conditions, the retardation was lower than as given above.

What I claim is:

1. Apparatus for receiving and amplifying telegraphic signals comprising in combination two radio-electro-sensitive elements, circuits including the same including electric generators, a third circuit to which the circuits of said radio-electro-sensitive elements are connected, the polarity of said electric generators being opposite with respect to such third circuit, an actuating element arranged to direct a beam of radiant energy upon both said radio-electro-sensitive elements, and by its operation to vary the illumination of such radio-electro-sensitive elements in opposite senses respectively, said beam normally illuminating substantial portions of both said radio-electro-sensitive elements, and a controlled element controlled by the said third circuit.

2. Apparatus for receiving and amplifying telegraphic signals comprising two radio-electro-sensitive elements, circuits including the same, electric generators in said circuits, a third circuit to which the circuits of said radio-electro-sensitive elements are connected, the polarities of said generators being opposite with respect to said third circuit, an actuating element arranged to deflect variably a beam of radiant energy across the surfaces of such radio-electrosensitive elements, the said beam when in mid-position covering a considerable portion of both said radio-electro-sensitive elements, and a controlled element controlled by the said third circuit.

3. Apparatus for receiving and amplifying telegraphic signals comprising two radio-electro-sensitive elements, a separate circuit for each such element, a third circuit to which the circuits of said radio-electrosensitive elements are connected in opposition, a galvanometer comprising a reflector arranged to deflect a beam of radiant energy variably across said radio-electro-sensitive elements, such beam when in mid-position covering a considerable portion of both said radio-electro-sensitive elements, and a controlled element controlled by said third circuit.

4. Apparatus for receiving and amplify ing telegraphic signals comprising two radio-electro-sensitive elements, a separate circuit for each such element, a third circuit to which the circuits of said radio-electro-sensitive elements are connected in opposition, a galvanometer comprising a reflector arranged to deflect a beam of radiant energy variably across said radio-electro-sensitive elements, such beam when in mid-position covering a considerable portion of both said radio-electro-sensitive elements, and a second galvanometer controlled by said third circuit and comprising signal-translating means operated by the operation of said second galvanometer.

5. Apparatus for receiving and amplifying telegraphic signals comprising in combination a radio-electro-sensitive element, a conductor mounted to oscillate, means producing a magnetic field influencing such conductor, a reflector oscillated by movement of said conductor and arranged to reflect variably a beam of radiant energy across the surface of such radio-electro-sensitive element, the rest position of such reflector corresponding to a condition of partial illumination of said radio-electro-sensitive element, a controlled element controlled by the circuit of said radio-electro-sensitive element, said controlled element comprising curbing windings, and a curbin circuit connected to such windings an controlling means for such circuit controlled by such controlled element.

6. In a telegraphy, a selenium relay comprising associated selenium cells arranged to form two arms of a VVheatstone bridge with suitable resistances in the other arms to balance the bridge, a source of current connected across one diagonal of the bridge, and a receiving instrument and an inductive resistance in shunt one to the other connected across the other diagonal of the brid e.

7 n telegraphy, a selenium relay having an inductive shunt around the receiving instrument adjusted to compensate for the inertia of the selenium.

8. In telegraphy, a radio-electric relay comprising associated radio-electro-sensitive cells arranged to form two arms of a "Wheatstone bridge with suitable resistances in the other arms to balance the brid e, a source of current connected across one iag- 'onal of the bridge, and a receiving instrument and an inductive resistance in shunt one to the other connected across the other diagonal of the bridge.

9. Apparatus for receiving and amplifying telegraphic signals comprising in combination two associated radio-electro-sensitive elements, a controlled device, a main circuit including that controlled device, two

branch circuits connected to said main circuit, one such branch circuit containing one such radio-electro-sensitive element, the other branch circuit containing the other radio-electro-sensitive element and batteries included one in one branch circuit and the other in the other branch circuit, the said batteries so arranged that the potential of the one battery opposes the potential of the other battery as to said main circuit.

10. Apparatus for receiving and amplifying telegra hic signals comprising in combination a i l heatstone bridge, radio-electrosensitive elements in the four arms of said bridge, a controlled device in the cross wire of the bridge, and a source of current supply connected to the two ends of the bridge, the said radio-electro-sensitive elements being arranged in pairs and the pairs being associated in such manner that increase or decrease of illumination of the radio-electro sensitive devices of such pairs affects such devices of each pair similarly, and that increase of illumination of one pair and corresponding decrease of illumination of the other pair afiect the controlled element similarl ll In telegraphy, a radio-electric relay comprising one or more radio-electro-sensitive elements and a receiving instrument controlled thereby, and an inductive shunt tro-sensitive element or elements.

12. In telegraphic apparatus of the kind referred to, the combination of a plurality of selenium cells arranged in separate branch circuits each connected with a generator, a receiving instrument also connected to said cells, and means for projecting a broad beam of light upon such cells and for moving such beam over the surfaces of such cells in such manner, that as the illumination of one cell is decreased the illumination of another cell is increased, theconnections being such that the potentials of the batteries of said selenium cells are normally opposed one to the other and balance each other when'the illumination of the cells is approximately equal, and that increase of illumination of one cell and decrease of illumination of the opposing cell cooperate to produce operation of the said receiving instrument.

13. In telegra hic apparatus of the kind referred to, a heatstone bridge and selenium cells in the arms of such bridge, in combination with a generator connected to the ends of such bridge and a receiving instrument contained in the cross wire of the bridge, and inductive resistance also in said cross wire and in shunt with respect to said receiving instrument.

14. The herein described method of transmitting, receiving and amplifying telegraphic si nals, which consists in transmitting signals through an electric circuit by currents of one polarity for one class of signals of the telegraphic code, and by currents of the opposite polarity for another class of signals of the telegraphic code, causing the signals so transmitted to vary the degree of illumination of cooperating radioelectro-sensitive elements in electric circuits electrically so connected with the receiving instrument that increase of illumination of one such element and decrease of illumination of the other element have a cumulative effect in reproducing and amplifying signals of the same polarity, said cooperating radio-electro-sensitive elements being each illumined to an intermediate and substantial degree when no signals are being transmitted, signals of one polarity causing decrease of illumination of one element and increase of illumination of its cooperating element, and signals of the opposite polarity causing increase of illumination of the element first referred to and decrease of illumination of its cooperating element, and causing the resulting current fluctuations in the circuits of said cooperating radio-electro-sensitive elements to operate electrical signaling means.

15. The herein described method of receiving and amplifying telegraphic signals, which consists in receiving signals transmitted through an electric circuit by currents of one polarity forone class of signals of the telegraphic code, and by currents of the opposite polarity for another class of signals of the telegraphic code, causing the signals to vary the degree of illumination of cooperating radio-electro-sensitive elements in electric circuits so connected electrically with the receiving instrument that increase of illumination of one such element and decrease of illumination of the other element have a cumulative effect in reproducing and amplifying signals of the same polarity, said cooperating elements being each illumined to an intermediate and substantial degree when no signals are being transmitted, signals of one polarity causing decrease of illumination of one element and increase of illumination of its cooperating element, and signals of the opposite polarity causing increase of illumination of the element first referred to and decrease of illumination of its cooperating element, and causing the resulting current fluctuations in the circuits of said cooperating radio-electro-sensitive elements to operate electrical signaling means.

In testimony whereof I have signed this specification in the presence of two subscribmg witnesses. v

THOMAS B. DIXON. Witnesses:

H. M. MARBLE, PAUL H. FRANKE. 

